Flush doors



July '16, 1957 Filed June l, 1955 E. G. STACK FLUSH DOORS 2 Sheets-sheet 1 In u'en for July 16, 1957 E.. G. s'rAcK 2,799,059

FLUSH DooRs Filed June 1, 1953 n A 2 Sheets-Sheet 2 United Safes Pafemo FLUSH DOORS Emmet G. Stack, Portland, Oreg.

Application June 1, 1953, Serial No. 358,807

3 Claims. (Cl. 20-35) This invention relates to coreless ush doors.

The door set forth in this application is an improvement on the door described in my application for Grain Doors, filed May 31, 1952, Ser. No. 290,858, in so far as its manufacture is concerned. The principle involved in both doors is the same, namely, that both cover sheets are arched inwardly until they come into contact at the center of the door where they are glued together over a small area as well as to the door frame which they cover. This construction providesva myriad of arches all of which cross at the center of the door. A door so constructed is so rigid that a core is not required.

In the application mentioned above I pointed out that for house doors I preferred to use a stile wide enough to take a mortise lockset and that I eased olf these Wide stiles so that the cover sheets could be brought into contact at the center of the door. This easing operation is a shaper job and one that does not lend itself to mass production.

The present invention is directed toward a more simplified, cheaper, and faster way of forming the door frame members and the cover sheets that they may be assembled into a coreless door employing the myriad arch principle.

How said members are formed is illustrated in the accompanying drawings in which Fig. 1 is a plan view of an assembled door frame; Fig. 2 is a plan view of the glue side of a cover sheet; Fig. 3 is a plan view of a nished coreless door; Fig. 4 is a cross section on the line 4 4 of Fig. 1; Fig. 5 is a cross section on the line 5-5 of Fig. l; Fig. 6 is a cross section of the door stile shown in Fig. 4, with the cover sheets secured thereto; Fig. 7 is across section similar to Fig. 6, but having the edge of the stile milled to a pattern; Fig. 8 is an enlarged cross section similar to Fig. 6, showing the groove before the sheets are arched; Fig. 9 is a cross section similar to Fig. 8, showing the groove distorted due to the arching of the cover sheets; Fig. 10 is a cross sectionbrokenon the line 10-10 of Fig. 3; Fig. 11 is a plan view of the corner assembly where the milled stile shown in Fig. 7 is used.

Thruout the `drawings and the specification similar numerals refer to similar parts.

The door frame A shown in Fig. 1, is made up of the stiles 1 and 2, the top rail 3, and the bottom rail 4, which may be made the same width as the top rail and stiles. These members 1, 2, 3, and 4, arerun straight four sides, an operation which may be carried out on any sticker or four side machine on a production line basis. These members may be assembled and held together in the rectangular kform by means of dowels (not shown) or by means of a mortise and tenon, and 6, respectively. The make-up of the door frame is so well known to those skilled in the manufacture of doors that no detailed description is necessary. The stile, milled to pattern, 7 may also be run on any sticker on a production line basis. However, the ends must be relished as shown at 8 in Fig. 11, that the stiles and rails may come into juxtaposition as shown in Fig. 1.

l2,799,059 Patented` July 16, 1957 As =a matter of convenience the drawings show the cover sheets 9 and 10 breakingsharply over the inner corners 11 ofthe stiles and rails and the arched portion 12 of thefcoversheets 9 and 10A as' formed with straight lines instead of being a reverse curve as it actuallyl is in reality. t t Y Fig. 2 shows the disposition of the glue areas 13 and 13A on the cover sheets 9 and 10. In other words, it indicates that the cover sheets 9 and v10 are glued to the flat parallel faces 14 and 15 of the stiles and rails numbered 1 to 4. Fig.2 yalso indicates that cover` sheets 9 and 10 are glued together at the center of the door by the glue area 13A when said cover sheets are brought into contact at this point. In order to bring said cover sheets 9 and 10 into contact at the center they must be depressed or arched inwardly toward each other. As the cover sheets 9 and 10 are depressed and break over the corners 11 of the stiles and rails the outer or exterior face 16 of said sheets is put in tension at the break-over point or the corners 11 while the inner -or interior face 17 is put in compression. To facilitate the depression of the central portion 12 of the cover sheets 9 and 10, I run a saw kerf or groove 18 on the interior face 17 of said sheets just inside the interior perimeter 19 of the door frame A. Fig. 9 shows how this groove 18 closes at the bottom 20 as the cover sheets are depressed or arched inwardly into contact.

'It is quite apparent that the cutting of this groove 18 weakens the cover sheets 9 and 10 by cutting down the area that would otherwise be present to resist shear of said cover plates when subjected to` loads adjacent the interior perimeter 19 of the door frame A.

This weakening of the cover sheets 9 and 10 by the cutting of the groove 18 may be compensated for in several ways, namely:

1. The cover sheets may be increased in thickness suicient to meet all contingencies.

2. The saw kerf or groove 18 may be lilled with glue as 21 which will more than make up for the material removed from said groove 18 when the glue 21 sets.

3. The stiles and rails may be milled as shown in Fig. 7, to provide point support of the cover sheets beyond the groove 18 as at 22.

Besides restoring full strength to the grooved cover sheets the filling of the groove 18 with the glue 21 is the most simple method and by far the cheapest. The groove 18 may be run thru as at 18A in order to make it easier to run. This extension 18A may also be lled with glue.

The door which I have described my be readily fabricated with equipment found in any small woodworking plant and it admits of fabrication on a production line basis in any door plant equipped to glue up ush doors.

Many modications may be made without departing from the basic idea set forth in this and my co-pending application 290,858 and I do not limit my invention to the exact disclosure herein but extend it to all that comes fairly within the scope of the appended claims.

What I claim as new in the at is:

l. A coreless flush door having a frame formed of stiles and rails, with at parallel glue faces, joined together at the corners to form a rectangular enclosure therebetween, a cover sheet glued to each parallel face of said stiles and rails, both cover sheets being depressed inwardly into contact within the enclosure to arch said cover sheets crosswise, lengthwise, and diagonally, said cover sheets being glued together at the point of contact with each other, each of said cover sheets having a groove formed on the glue side thereof adjacent to and paralleling the stiles and rails forming the enclosure to facilitate the depression of the cover sheets.

2. A coreless ush door having a frame formed of stiles and rails, with flat parallel glue faces, joined together at the corners to form a rectangular enclosure therebetween, a cover sheet glued to each parallel face of said stiles a'nd rails, one of said-cover sheets vbeing depressed inwardly into Contact within the enclosure to arch saidv cover s'heetcros'swise;= lengthwise, and diagonally, Y said cover sheets being f glued together atv the point of contact withv each other, said depressed 'cover sheet having' a groove formed on the glue side thereof adjacent to and parallelin'gY the stiles and rails 'forming the enclosure to facilitate the depression of said cover sheet.

3. The addition to the structurey ofgclairn 1 of glue to ll the groove-in the cover sheets to compensate for the material removed from the grooves when said vglue sets.

References Cited in the file of this patent UNITED STATES PATENTS Alexander Nov. 28, 1939 Norquist May 2, 1950 FOREIGN PATENTS France Dec. 18, 1925 Germany Aug. 19, 1939 Great Britain July 24, 1942 

